If you are unable to sign in with what you know to be your correct username and password, please ensure that you have cookies enabled. If your cookies are already enabled or enabling them doesn't resolve this issue, try clearing the browser's cache.

Some Mac OSX users have reported trouble logging in using Safari. In our own testing with Safari on Mac OSX, we have been unable to reproduce the problem. In some cases, turning off Private Browsing seems to have made a difference, however this hasn't been universally true. We continue to look into the issue and will provide updated information when it becomes available.

In the meantime, we recommend trying either Mozilla Firefox or Mozilla Camino as alternative browsers that have been successfully tested.

UPDATE 20081015: We have heard that OSX 10.5.5 fixes this issue.

Enable cookies for Internet Explorer 7

1. Click “Start” and select “Control Panel”.

(Note: With Windows XP Classic View, click the Windows “Start” button, then select “Settings” and “Control Panel”).

1. Open the Internet Options icon.
2. Choose the “Privacy” tab.
3. Click the “Advanced” button.
4. Check the box “Override automatic cookie handling” under the Cookies section in the Advanced Privacy Settings window.
5. Under First-party Cookies, select the “Accept” or “Prompt” option.
6. Under Third-party Cookies, select the “Accept” or “Prompt” option.
   (Note: If you select the “Prompt” option you will be prompted every time a Web site attempts to send you a cookie to click “OK”.)
7. In the Internet Options window, click “OK” to exit.
8. If this doesn't solve the issue, try: Clear the cache for Internet Explorer

Enable cookies for Internet Explorer 6

1. Click “Start” and select “Control Panel”.
2. (Note: With Windows XP Classic View, click the Windows “Start” button and select “Settings” and “Control Panel”) Select the “Privacy” tab.
3. Click the “Advanced” button.
4. Place a check in the “Override Automatic Cookie Handling” check box.
5. Under First Party Cookies, select the “Accept” or “Prompt” option.
6. Under Third Party Cookies, select the “Accept” or “Prompt” option.
7. (Note: If you select the “Prompt” option you will be prompted every time a Web site attempts to send you a cookie to click “OK”.) In the Internet Options window, click “OK” to exit.
8. If this doesn't solve the issue, try: Clear the cache for Internet Explorer

Enable cookies for Mozilla Firefox -x (PC)

1. In Mozilla Firefox, select “Tools” from the file menu.
2. Select “Options”.
3. Click on the “Privacy” icon in the top panel.
4. Check the box corresponding to “Accept cookies from sites”.
5. Click “OK” to save and close.
6. If this doesn't solve the issue, try: Clear the cache for Firefox -x (PC).

Enable cookies for Mozilla Firefox -x (PC)

1. In Mozilla Firefox, select “Tools” from the file menu.
2. Select “Options”.
3. Click on the “Privacy” icon in the top panel.
4. Click on the “Cookies” tab.
5. Check the “Allow sites to set cookies” checkbox.
6. Click “OK” to save and close.
7. If this doesn't solve the issue, try: Clear the cache for Firefox -x (PC).

Enable cookies for Mozilla Firefox (Mac)

1. Go to the “Firefox” drop down menu.
2. Select “Preferences”.
3. Select the “Privacy” icon.
4. Under “Cookies”, mark the checkbox for “Allow sites to set Cookies”.
5. If this doesn't solve the issue, try: Clear the cache for Firefox (Mac).

Enable cookies for Safari

1. Go to the “Safari” drop down menu.
2. Select “Preferences”.
3. Select the “Security” icon at the top panel.
4. Under “Accept Cookies” section select “Only from sites you navigate to”.
5. If this doesn't solve the issue, try: Clear the cache for Safari.

If your cookies were already enabled or enabling cookies doesn't resolve the problem, you may also want to clear the cookies that are stored on your computer (Please note that while clearing your cookies may resolve the problem, it will also remove your saved settings for sites you've previously visited.)

Clear the cache for Internet Explorer 7

1. Click “Start” and select “Control Panel”.

(Note: With Windows XP Classic View click the Windows “Start” button and select “Settings” and “Control Panel”).

1. Open the “Internet Options” icon.
2. Click on the “General” tab if it isn't selected already.
3. Under the Browsing history section, click the “Delete…” button.
4. Click the “Delete cookies…” button.
5. Select “Yes” if a box appears to confirm.
6. Click “OK” to close the window.

Clear the cache for Internet Explorer 6

1. Click “Start” and select “Control Panel”.

(Note: Windows XP Classic View click the Windows “Start” button and select “Settings” and “Control Panel”)

1. Open the “Internet Options” icon.
2. Click on the “General” tab if it isn't selected already.
3. Under the heading “Temporary Internet files,” click the “Delete Cookies…” button.
4. Click “OK” for the “Delete all cookies in the Temporary Internet Files folder?” prompt.
5. Click “OK” to exit.

Clear the cache for Mozilla Firefox -x (PC)

1. In Mozilla Firefox, select “Tools” from the file menu.
2. Select “Options”.
3. Under the “Private Data” heading, click the “Clear Now” button.
4. Click “OK” to exit.

Clear the cache for Mozilla Firefox -x (PC)

1. In Mozilla Firefox, select “Tools” from the file menu.
2. Select “Options”.
3. Click on the “Privacy” icon in the top panel.
4. Click on the “Cookies” tab.
5. Check the “Clear Cookies Now” button.
6. Click “OK” to save and close.

Clear the cache for Mozilla Firefox (Mac)

1. Go to the “Firefox” drop down menu.
2. Select “Preferences.”
3. Select the “Privacy” icon.
4. In version -5, click “Clear Cache Now.” In -0, next to “Cache,” click the “Clear” button, and then “OK.” In -0, click on the “Clear Now” button under the “Private Data” heading.

Clear the cache for Safari

1. Go to the “Safari” drop down menu.
2. Select “Preferences”.
3. Select the “Security” icon at the top panel.
4. From the Security dialog box, click “Bookmarks”.
5. Click “Show Cookies”.
6. From the Cookie dialog box, click to choose cookies from youtube.com, and click “Remove”. Alternatively, if you want to delete all cookies, click “Remove All”.
7. Click “Done”.